To research the cutting mechanism of a metal cutting process, various tool quick-stop devices are widely used at present. Through tool quick-stopping in the cutting process, the samples of deformation region and chip root under the cutting conditions are obtained. Then, the samples are observed through different methods. Physical models formed by all kinds of cutting are established to reveal the metal cutting mechanism to achieve the purpose of describing or predicting the cutting process. To enable the cutting root sample to be closer to a state during cutting, the quick-stop device must be designed in such a manner that the falling acceleration of the tool is large enough, the separation time of the tool and the workpiece is short as much as possible, the motion track of the tool tip is reasonable during tool falling and the cutting root should be influenced to the minimum degree in the separation process of the tool and the workpiece.
At present, common tool quick-stop devices for a lathe include a hand hammer type, a shooting type, an explosion type, etc. The hand hammer device has large vibration during beating of a hand hammer, which influences tool cutting and the precision of the machine tool. The shooting device has high operation danger coefficient. The explosion device is uneven in acceleration, the initial acceleration value is less than a later obtainable value; and the operation is complicated; the drug consumption for explosion and shear force required for pin shearing are difficult to be accurately calculated; and the operation is unsafe and noise is large. The above tool quick-stop devices need to cut off shear pins. At present, some patents avoid the damage to the shear pins through structural design, the tool falling is in such a manner that the tool rotates, but the rotating axis of the tool is lower than a horizontal plane of the turning center, so that the falling motion track (arc) of the tool tip is intersected with the excircle of the workpiece, causing that the tool tip extrudes the workpiece and the chip root and the tool tip are adversely affected. If compression of the spring is used as the power, the end surface of the spring is not close to the tool surface in the rotation of the tool and the spring cannot always keep good contact with the tool bar, causing a tool falling acceleration error.